First of all, it should be said that with brief exceptions Roubini has been saying this for about the last decade, ever since the end of the financial crisis. He was right in 2007-08, which is how he made a name for himself. The problem is that he's a permabear, so of course he's going to be right again at some point.
There's a lot of leverage in the system generally. The thought is that the rout in oil along with impacts of the virus could create a tightening in high yield credit generally (lots of smaller oil companies fall into that category), and then that ripples through the broader credit market. Not saying it won't happen, but the banks are also fairly well-capitalized right now. Europe's are not.